JP4765410B2 - Active vibration noise control device - Google Patents

Description

  The present invention relates to an active vibration noise control device, and more particularly to an optimal arrangement configuration of vibration detection sensors in an active vibration control device (AVC) and an active noise control device (ANC) mounted on a vehicle.

  Conventionally, in order to suppress vehicle interior noise generated by vibrations transmitted through the vehicle body panel, control vibration that cancels the vibration is generated in the vehicle body panel, or active vibration suppression that generates control sound that cancels the noise is generated in the vehicle interior. Techniques are known (see, for example, Patent Document 1 and Patent Document 2).

  Patent Document 1 discloses an active vibration control device (AVC) in which an H∞ control circuit calculates the vibration of a vehicle body detected by an error sensor and controls an actuator based on the calculation result.

Patent Document 2 discloses an active noise control device (ANC) that cancels out noise in the vehicle interior by controlling the sound emitted by the sound radiating means based on the detection signal of a vibration detector attached at or near the door hinge. Has been.
JP 2000-259158 A (refer to paragraph 0007 in particular) Japanese Unexamined Patent Publication No. Hei 8-2922771 (see in particular paragraph 0008)

  However, Patent Documents 1 and 2 disclose that noise is suppressed by using a sensor that detects vibration of a vehicle body panel instead of a microphone that measures noise in a vehicle interior. There is no detailed description of what should be placed in the.

  Therefore, when the sensor is attached to the vehicle body, if it cannot be arranged at an optimal location, the vibration / noise control accuracy will be reduced. On the other hand, if more sensors than necessary are arranged in order to maintain control accuracy, the cost increases.

A feature of the present invention is that a plurality of sensors arranged on the floor panel of the vehicle body for measuring the vibration of the vehicle body, and a noise for calculating a vehicle interior noise due to the vibration of the vehicle body based on the vibration of the vehicle body measured by the sensor Vibration of the vehicle body is generated by controlling the active unit according to the noise in the vehicle interior calculated by the calculation unit, the vehicle body generating control vibration or generating the control sound in the vehicle interior, and the noise calculation unit. The floor panel is divided into a plurality of areas by members whose rigidity value is larger than the average value of the rigidity values of the entire floor panel, and the plurality of sensors are The gist is that they are arranged in each region delimited by members .

  According to the present invention, an active vibration noise control device that reduces the number of sensors and reduces the cost of the sensor while maintaining high vibration / noise reduction performance can be provided because the sensor can be arranged at an optimal location. I can do it.

  Embodiments of the present invention will be described below with reference to the drawings. In the description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

[Overall configuration of active noise control system]
As shown in FIG. 1, an active noise controller (ANC: Active Noise Controller) according to an embodiment of the present invention measures a first sensor 1 that measures vibration transmitted to a vehicle body 5 and vibration transmitted to the vehicle body 5. A second sensor 2 that calculates noise in the vehicle interior due to vibration of the vehicle body 5 based on vibrations of the vehicle body 5 measured by the second sensor 2, and control vibrations in the vehicle body 5 or in the vehicle interior. A speaker 3 as an example of an active unit that generates a control sound, and a control sound emitted by the speaker 3 based on the vibration of the vehicle body 5 measured by the first sensor 1 and the vehicle interior noise calculated by the noise calculation unit 12. And a controller 4 to be controlled. In addition, although ANC is demonstrated as an Example, this invention is applicable also to an active vibration control apparatus (AVC: Active Vibration Controller).

  The controller 4 cancels and reduces the vibration and noise by causing the control sound emitted by the speaker 3 to interfere with the vibration and noise transmitted from the outside of the vehicle body 5 to the vehicle interior. There are a plurality of controllers that actively reduce vibration and noise by interfering with control sound. Here, as an example, there is an adaptive filter 7 that transmits a control signal to the speaker 3 and a vehicle interior noise. The controller 4 (adaptive filter controller) provided with the adaptive row | line | column 8 which updates a filter parameter on-line using the processed signal is shown.

  As shown in FIG. 4, in a general active noise control apparatus using an adaptive filter controller, two types of signals measured by two types of sensors (1, 53) are required. One is a signal related to a disturbance that causes noise transmitted to the vehicle interior. For example, the signal from the acceleration sensor (G sensor) 1 that measures vibration transmitted from the road surface 11 to the wheels (tires 10a and 10b). A signal is included. The other is a signal related to the noise level in the vehicle, and includes, for example, a signal from a microphone 53 mounted in the vehicle. That is, in the active noise control apparatus using the adaptive filter 7, as a sensor for measuring a physical quantity related to the vibration of the vehicle body, a sensor (acceleration sensor 1) for measuring disturbance, vibration or noise due to the disturbance, and control sound by the speaker 3 are used. As a result of the interference, two types of sensors are required: a sensor (microphone 53) that measures noise transmitted in the vehicle.

  On the other hand, in the case of the embodiment of the present invention (FIG. 1), the signal is transmitted from the road surface 11 to the wheels (tires 10a and 10b) as means for detecting a signal related to the disturbance that causes noise transmitted to the vehicle interior. An acceleration sensor (G sensor) that measures the vibration generated is used as the first sensor 1. On the other hand, as means for detecting a signal related to the noise level in the vehicle, an acceleration sensor (second sensor 2) that measures vibration transmitted to the vehicle body 5 and the vibration of the vehicle body 5 measured by the second sensor 2 are used. And a noise calculation unit 12 for calculating noise in the passenger compartment due to vibration of the vehicle body 5. That is, the second sensor (G sensor) 2 and the noise calculation unit 12 are provided instead of the microphone 53 of FIG. 4 in a general adaptive filter controller.

  As shown in FIGS. 8A and 8B, the floor panel 6 of the vehicle body 5 to which the first and second sensors 1 and 2 of FIG. 1 are fixed is divided into three main parts. Can do. Specifically, the floor panel 6 includes a flat cabin panel 15 positioned below a seat on which an occupant sits, a tank panel 16 to which a fuel tank is fixed, and a spare tire panel positioned below a spare tire and a trunk. 17. The cabin panel 15 is located between the engine room and the tank panel 16. The spare tire panel 17 is located between the tank panel 16 and the rear end of the vehicle body 5.

  As shown in FIG. 9, on the floor panel 6 of FIG. 8 (b), there are four vertical members 18a-18d extending in parallel in the traveling direction of the vehicle and four horizontal members 19a-19d extending vertically. And are arranged. Since the floor panel 6 is formed in a thin flat plate shape to reduce the weight of the vehicle body, sufficient rigidity cannot be obtained with the floor panel 6 alone. The bar-shaped vertical members 18a to 18d and the horizontal members 19a to 19d having higher rigidity than the floor panel 6 are fixed on the floor panel 6 to increase the rigidity of the floor panel 6. The vertical members 18 a to 18 d and the horizontal members 19 a to 19 d are formed thicker than the floor panel 6. The vertical members 18a to 18d and the horizontal members 19a to 19d may be fixed only to one surface (front surface or back surface) side of the floor panel 6, or may be fixed to both surfaces (front and back surfaces).

[Relationship between body panel vibration and noise transmitted to the passenger compartment]
Next, the relationship between the vibration of the floor panel 6 and the noise transmitted to the passenger compartment will be described using equations (1) to (5).

All sounds transmitted to the passenger compartment can be divided into sounds transmitted from the engine and road surface and sounds useful for the passengers including conversations between the passengers and sounds from the audio. The sound transmitted from the engine or the road surface corresponds to so-called noise N _R that is undesirable for the passenger.

The noise N _R is generated by tire / wheel vibration or engine vibration due to road surface unevenness. These vibrations theoretically spread over the entire vehicle body and the entire vehicle body panel, and the noise caused by the vibration of the vehicle body panel is called “road noise”.

However, the floor panel of the vehicle body panel has a large surface area and has a short physical distance to the tire, for example, compared to the roof panel. The wheel is partially connected directly to the floor panel. Therefore, the contribution ratio of the vibration of the floor panel to the noise N _R is considered to be large.

As a result, it can be said that the noise N _R in the vehicle interior can be obtained only by vibration of the floor panel rather than the sound level by the microphone arranged in the vehicle interior. In this case, it is possible to actively suppress only the noise N _R that is not desirable for the occupant, and to leave other radio sounds measured by the microphone, occupant conversations, and the like as they are.

To effectively reduce the noise N _R of the passenger compartment from the vibration of the floor panel, matching rate between the noise transmitted to the vibration and the vehicle interior floor panel (Coherence function) is used.

  The matching rate is a degree of correlation between one or more signals and one signal, and is defined by a numerical value of 0-1. For example, when the signal B is the result of a phenomenon in which only the signal A is input, the matching rate between the signals A and B is defined as 1. On the contrary, when the signal B is the result of a phenomenon in which the signal A is not input, the matching rate between the signals A and B is defined as zero.

When the matching rate C _xy (ω) is a matching rate between the signal x and the signal y in the vibration ω (rad / s), it can be defined by the equation (1). Further, S _xy (ω) and S _xx (ω) in the equation (1) are defined by the equation (2).

P _ab (ω) in the equation (2) indicates an automatic spectrum at the vibration ω when a = b, and indicates a cross spectrum between a and b at the vibration ω when a = b is not satisfied. The signal x can be composed of N signals xi as shown in equation (3).

By using the matching rate, as shown in FIG. 6B, P _xx having a large contribution rate to P _yy can be obtained, and this is set as P _zz (= P _xx ). P _xx having a small contribution ratio with respect to P _yy can be obtained, and this is defined as P _ee (= P _xx ). As shown in FIG. 6A, the signal e (t) is mixed with the signal z (t) to become the signal y (t).

The distribution ratio of P _zz (ω) and the distribution ratio of P _ee (ω) with respect to P _yy (ω) are calculated according to equations (4) and (5), respectively.

As shown in FIG. 6C, the vibration of the wheels of the tires 10a to 10d spreads over the entire floor panel 6. If the vibration of the floor panel is x (t), the vibration x (t) is detected by the first and second sensors 1 and 2 arranged on the floor panel. Assuming that the noise generated in the vehicle interior due to the vibration x (t) is z (t), as shown in FIG. 6 (a), the vibration x (t) is a noise z (t) according to a predetermined function H (s). Will be converted to. Then, the noise z (t) resulting from the vibration x (t) is expressed as a sound in which other sounds e (t) such as wind sound, passenger conversation, audio sound, etc. generated by traveling of the vehicle are mixed. Assuming that (t) , when the microphone is arranged in the vehicle interior, the microphone measures the sound y (t) . Therefore, if the sound y (t) measured by the microphone is P _yy in FIG. 6B, for example, the matching rate of noise z (t) is P _zz and the matching rate of sound e (t) is P _ee .

  The inventors actually run the vehicle and conduct an experiment to measure the sound and vibration in the passenger compartment using a microphone placed at the position of the passenger's ear and an acceleration sensor (G sensor) placed on the floor panel. It was. The experiment was conducted in the absence of sound from the occupant, audio and navigation system. As a result of this experiment, it was proved that the contribution ratio of the noise due to the vibration of the floor panel to the sound transmitted to the passenger compartment is 70% or more, that is, the matching ratio is 0.7 or more. In particular, it was found that the matching rate at 100 to 200 Hz and 300 to 400 Hz was 0.8 to 0.9.

  Therefore, the vibration of the floor panel 6 can be detected, and the noise in the vehicle compartment can be calculated from the vibration using the matching rate.

  Therefore, in the active vibration noise control device of the embodiment including the active vibration control device (AVC) and the active noise suppression device (ANC), instead of measuring the sound transmitted to the vehicle interior with the microphone, the vibration transmitted to the floor panel is measured. Measured by the acceleration sensor (second sensor 2), the controller 4 changes to use the signal from the acceleration sensor without using the signal from the microphone.

  Here, the advantage of the vibration measurement of the floor panel 6 compared with the measurement of the sound transmitted to the vehicle interior is as follows.

  1. Installing the acceleration sensor (second sensor 2) on the floor panel 6 is easier than installing microphones near the left and right ears of each occupant. In this case, the length of the harness to be used is shorter for the acceleration sensor than for the microphone.

  2. Noise that is undesirable for the passenger is mainly the sound transmitted from the tire / wheel through the vibration of the floor panel, so the contribution ratio of the vibration of the floor panel to this noise is the sound measured by the microphone placed in the passenger compartment. Can be obtained with higher accuracy than the contribution ratio.

  Next, an example in which the present invention is applied to an active noise control device (ANC) will be described.

  First, with reference to FIG. 4 and FIG. 5, the configuration of a general active noise control device (ANC) will be described as a comparative example of the embodiment.

  There are various controllers for reducing vibration and noise, but the adaptive filter controller 4 shown in FIG. 4 is one of the most frequently used controllers. The adaptive filter controller 4 achieves a predetermined purpose by updating parameters of the adaptive filter 7 online. The predetermined purpose here is to cancel vibration or noise transmitted to the vehicle body 5. The parameter update is performed according to the adaptive row 8.

  The adaptive filter controller 4 includes an adaptive filter 7 that transmits a control signal to the speaker 3 and an adaptive low 8. In the active vibration control apparatus using the adaptive filter 7, as a sensor, the noise (acceleration sensor 1) that measures the disturbance and the noise or the noise transmitted through the vehicle as a result of interference between the vibration or noise caused by the disturbance and the control sound from the speaker 3 are detected. Two types of sensors to be measured (microphone 53) are required. Note that the speaker 3 generates a control sound in the vehicle interior to cancel vibration or noise caused by disturbance.

  As shown in FIG. 5, a signal related to the disturbance X is transferred to the adaptive filter 7. At the same time, the disturbance X is also transmitted to the system 9. The system 9 is a superordinate concept including the vehicle body 5 in FIG. Further, the signal related to the disturbance X is a reference signal, and is transferred from, for example, the sensor 1 in FIG. The adaptive filter 7 generates a response signal y (n) for the reference signal x (n) related to the disturbance X and supplies it to the speaker 3. The adaptive filter 7 can eliminate or reduce the noise in the passenger compartment by updating the filter parameters according to the adaptive row 8.

  As shown in FIG. 5, the entire system 9 controlled by the active vibration control device is represented by, for example, a transfer function form model G (z), and the model G (z) is further divided into two parts. Can be divided.

  The first part corresponds to the scattering of vibration from the disturbance source X to the actuator (speaker) 3 on the vehicle body 5 or the floor panel 6 and is characterized by, for example, a transfer function type model F (z). This model F (z) represents vibration due to disturbance transmitted to the vehicle body 5 or the speaker 3 on the floor panel 6 via the tires 10a and 10b.

  The second part corresponds to a sound wave transmitted from the speaker 3 to the microphone 53 or a measurement point for measuring the sound level in the passenger compartment, and is characterized by, for example, a transfer function type model C (z). The second part represents the period from the generation of sound by the speaker 3 to the measurement of the noise level in the vehicle by the microphone 53.

  It is generally difficult to accurately measure or evaluate an actual vibration model. This is because it is difficult to accurately know the number and arrangement of the disturbance sources X. However, it is possible to determine the acoustic model C (z) 13 accurately. This is because the number and arrangement of the speakers 3 can be accurately known, and the arrangement of the acceleration sensor 1 or the microphone 53 for measuring vibration and volume can also be accurately known.

  The main advantage of the adaptive filter controller 4 is that it is not necessary to measure the vibration model of the system 9. The model F (z) is evaluated online from the signal X (n) of the disturbance source and the signal e (n) corresponding to the sound level.

  As shown in FIG. 5, the control loop is characterized by a loop of F (z) A (z) C (z). Here, F (z) represents a transfer function of the adaptive filter 7, and the signal y is transferred from the model F (z) to the speaker 3 of the transfer function A (z). The sound from the speaker 3 is represented by an acoustic model C (z) from the speaker 3 to the passenger's ear. The sound level is measured by the microphone 53 of the transfer function S (z).

  In order to simplify the system, the dynamic system of the speaker 3 and the microphone 53, for example, the transfer functions A (z) and S (z) can be ignored. However, strictly speaking, it is desirable to take into account noise control.

In order to simplify the notation, all transfer functions can be expressed by an FIR (finite impulse response) model as shown in equation (6).

The output y _c of the control loop F (z) A (z) C (z) representing the sound is added to the output g of the actual system 9 (u = g + y _c ) and becomes zero in a predetermined frequency band. Is calculated as follows.

In practice, the parameter f _φ of the adaptive filter F (z) is adjusted so that the output y _c interferes with the output g and cancels each other. The signal e (n) corresponding to the volume in the passenger compartment is a signal measured by the microphone 53, for example. Alternatively, it may be a signal measured by an acceleration sensor (G sensor) disposed in the vehicle body 5 corresponding to the volume in the vehicle interior.

The adaptive filter F (z) is generally represented by an FIR filter as shown in Equation (7). The number of parameters f _phi adaptive filter F (z) and phi _m. The variable φ varies from 0 to (φ _m −1).

Here, z ⁻ⁱ is a variable of Z conversion, and is expressed by equation (8). In equation (8), h (n) is a sample signal.

Therefore, the output y (n) of the adaptive filter F (z) is expressed by equation (9).

The signal e (n) indicating the sound volume in FIG. 5 is expressed by equation (10).

The model S (z) of the microphone 53 can be expressed not only by the FIR filter but also by the IIR filter. The model S (z) is represented by an FIR filter having σ _m parameters. Reference value J to be minimized by the adaptive row 8 to calculate the parameters f _phi is defined by equation (11).

The parameters γ _e and γ _y are fixed by the user. When the differential value of the reference value J shown in the equation (12) becomes zero, the reference value J reaches the minimum value.

Here, the signal r (ni) is defined by the equation (13).

Adaptive Low 8, (14) in accordance with equation to update the parameter f _phi adaptive filter F (z) from (n) to (n + 1). Here, n indicates the number of updates, and K is fixed by the user.

Equation (14) can be further rewritten into Equation (15).

(15) the parameters Λ and Γ in formula are respectively set by the user, equal respectively to 2Keiganma _e and 2Keiganma _y, less than 1. The parameter Λ is a parameter for fixing the convergence speed of the adaptive filter F (z) to the optimum value, and the parameter Γ is a parameter for fixing the convergence safety.

In general, the initial value set f _φ (0) of the parameter f _φ of the adaptive filter F (z) is set to all zero for simplification and generalization. The simplification means is omitted initial value set f φ ₍₀₎ and special memory for saving a means for calculating and evaluating the set of initial values f φ _(0). Generalization means that the state of the vehicle differs depending on the type of vehicle, and the parameter _fφ converges toward an optimum value corresponding to J (optimum value) corresponding to the minimum value of the noise level in the passenger compartment. .

  Next, the active noise control apparatus (ANC) according to the embodiment will be described with reference to FIGS. 1 to 3.

  In the active noise suppression apparatus according to the embodiment, active noise control is performed using an error signal from the noise calculation unit 12, as shown in FIG. 2, instead of the error signal from the microphone 53 in FIG.

  The error signal from the noise calculation unit 12 is used only in the case of ANC instead of the error signal from the microphone 53 of FIG. The signals input to the noise calculation unit 12 are acceleration α measured at a plurality of locations on the vehicle body panel and a signal y transferred to the speaker 3.

As shown in FIG. 3, the acceleration α is input to the acoustic system M (z). The acoustic system M (z) corresponds to an acoustic system between the acceleration α and the sound pressure level (SPL), and the sound pressure level (SPL) is calculated off-line in consideration of values at a plurality of points. The signal y is input to the transfer function (A × C) including the speaker 3 and the acoustic model. Each of the acceleration α and the signal y, which have been subjected to arithmetic processing, are mixed to form a signal e and transferred to the adaptive row 8 in FIG. Therefore, the signal e (k) is expressed by equation (16).

  The adaptive row 8 in FIG. 2 has the same configuration as that in FIG.

  Next, an example where the present invention is applied to an active vibration control apparatus (AVC) will be described with reference to FIGS.

  The AVC generates the control vibration on the floor panel 6 and the vehicle body panel using the actuator 20 and interferes with the vibration transmitted from the tires 10a and 10b to the floor panel 6 and the vehicle body panel. Reduce the sound pressure level (SPL). Usually, the actuator 20 is fixed on the floor panel 6 or the vehicle body panel where the vibration is greatest, and is feedback controlled. Therefore, one or a plurality of sensors 1 that measure vibration are required. Generally, the actuator 20 and the G sensor 1 are arranged on the floor panel 6 in a pair.

  In AVC, information on the sound pressure level SPL in the passenger compartment may be supplied to the controller 4b. As described in the ANC, in this case, the sound pressure level SPL can be calculated from the vibration measured by the G sensor 2 of the floor panel 6 instead of the microphone arranged in the vehicle interior.

  In the case of AVC, the G sensor (first sensor) 1 for active vibration control and the G sensor (second sensor) 2 that measures the vibration of the floor panel to calculate the sound pressure level SPL are different functions. Have a purpose.

  In the AVC according to the embodiment, the vibration of the floor panel 6 measured by the second sensor (G sensor) 2 shown in FIG. 11 is used instead of the sound pressure level SPL in the vehicle compartment measured by the microphone 53 of FIG. To control the sound pressure level SPL in the passenger compartment. As the controller 4b, not only an adaptive controller including an adaptive filter and an adaptive low can be used in the same manner as ACN, but also a fixed gain controller can be used. The gain fixing controller 4b fixes the gain of the controller 4b and distorts the actuator 20 based on a signal from the acceleration sensor 1 that measures vibration transmitted from the road surface 11 to the wheels (tires 10a and 10b). Thus, by generating distortion in the floor panel 6, control vibration is generated in the vehicle body 5 to cancel vibration or noise due to disturbance.

The system showing between the actuator 20 and the vibration can be expressed by various models. Here, a state space model as shown in the equation (17) is used.

Here, u (k) indicates a signal transmitted to the actuator 20, α (k) indicates vibration at a specific position on the floor panel, and A, B, C, and D are systems in consideration of the system. Is a matrix. The control signal u (k) can be expressed by equation (18). Here, K can be obtained by, for example, the H ₂ or H _∞ control method.

When the G sensor 2 is used as the second sensor as shown in FIG. 11 instead of using the microphone 53 of FIG. 10, the expression (17) is changed to the expression (19). The output y (k) is expressed by equation (20).

Here, n in the equation (20) indicates the number of sensors used for vibration control, and m indicates the number of sound pressure level measurement points. Actually, SPL _i is not measured by the microphone, but is calculated based on the vibration measured by the second sensor 2 by the noise calculation unit 12 in the ANC and the signal from the controller 4b.

Expression (18) is changed to Expression (21).

[Optimization of sensor placement and number]
As described above, there is a close relationship between the vibration of the floor panel and the noise transmitted to the position of the passenger's ear in the passenger compartment. That is, the matching rate of both is very large. Therefore, it is predicted that the noise from the road surface can be efficiently evaluated by measuring the vibration of the floor panel.

  Theoretically, in order to efficiently evaluate the noise from the road surface, it is most desirable to measure the vibration of the entire floor panel. However, it is impossible in practice, and it is desirable to reduce the number of G sensors as much as possible in consideration of the reliability and cost of the system. Thus, the following two items are required.

1. 1. Determine the number of sensors that are least Determining the optimal placement of sensors on the floor panel In these matters, several criteria are required: The first is the arrangement of the sound pressure level SPL, that is, the position of the passenger's ears and the number of passengers. The second is the speed of the vehicle.

  The number of sensors is obtained using, for example, PCA (principal component analysis). PCA determines the number of sensors that are “heavy” and ignores those that are “heavy”.

Specifically, an experiment is performed in which vibration is measured using a plurality of sensors arranged at equal intervals on the floor panel. Next, PCA processing is performed. In the PCA process, the value of S _xx (ω) in equation (2) is calculated for each value of ω. In equation (22), the matrix Λ includes a singular λ i of N signals measured by N G sensors on the floor panel.

The magnitude relationship of N singular λi, which are positive values, is shown in equation (23).

  Theoretically, when the number of singular λ is strictly 0 or more, the number of singular λ is the number of required sensors. However, in practice, the singular λ is slowly attenuated to around zero. Therefore, a predetermined threshold value that is considered to be sufficiently small in the number of singular λ is set. Thereby, the number of singular λ below the threshold can be ignored. Similarly to the change of the single λ according to the wave ω, the threshold value also changes according to the wave ω.

In order to avoid the change of the threshold according to the wave ω, the attenuation rate η _i (ω) shown in the equation (24) is introduced.

The attenuation rate η _i (ω) is the attenuation rate [dB] of the single λ compared to the largest single λ ₁ in the wave ω. In other words, the largest single λ is set as a reference value (η ₁ (ω) = 0), and the attenuation rate of the other single λ is calculated. The merit of the attenuation rate η _i (ω) is that the threshold value can be made constant for all the waves ω.

Due to the attenuation factor η _i (ω), the number of sensors is equal to the number of singular λ greater than the threshold. Here, the threshold value can be set to −40 dB, for example.

FIG. 12 shows the frequency dependence of the vibration damping rate measured by 16 sensors arranged on the floor panel. When the threshold is set to −40 dB, the number of necessary sensors is 100 to 600 Hz. The threshold is determined by the total cost of the control system and the theoretical accuracy of the control (noise control assessment). From the total cost of the control system, the maximum number of sensors can be estimated. In the case of a general ANC, the theoretical noise removal achievement value γ [dB] is obtained by the equation (25).

  Here, the vector x includes acceleration at a measurement point on the floor panel, and the vector y indicates a sound pressure level SPL at a predetermined position in the passenger compartment.

  Next, the floor panel position on which the above-mentioned minimum number of G sensors are desirably arranged, that is, determination of the optimum arrangement of G sensors will be described. A case will be described where the minimum number of sensors is calculated to be p in the above-described PCA.

  In the present embodiment, p G sensors are evenly distributed in a plurality of regions dividing the floor panel. The plurality of regions are separated by a strong structure having high rigidity. For example, an area delimited by members 18a to 18d and 19a to 19d shown in FIG. 9 corresponds to this. In FIG. 9, the floor panel 6 is divided by four members in each of the vertical and horizontal directions. However, as shown in FIG. 13, the floor panel 6 is divided into four regions A by two strong structures of the tunnel 23 and the tank gap 24. It is also possible to divide into ~ D. The tunnel 23 is a structure in which the center of the floor panel 6 is arranged in parallel with the traveling direction of the vehicle. The tank gap 24 is a structure that is disposed perpendicular to the traveling direction of the vehicle and separates the fuel tank and the vehicle interior. The p sensors are arranged so as to be evenly distributed in these regions A to D.

  With reference to FIGS. 14 to 17, a simulation performed by the inventors on a type of vehicle generally called a compact car will be described. Here, a case where eight G sensors are necessary as the second sensor 2 by PCA will be described.

  As shown in FIGS. 14 and 15, vibrations are measured at a plurality of locations on the entire floor panel 6, and microphones 53 a are arranged at two locations, the right ear position of the driver and the right ear position of the occupant in the rear right seat. The sound pressure level was measured by placing 53b. FIG. 14 shows a case where all the G sensors 2a to 2h are arranged behind the tank gap 24, that is, on the tank panel 16 or the spare tire panel 17, and in FIG. A case where two G sensors 2i to 2p are arranged in each of the four regions A to D is shown.

FIG. 16 and FIG. 17 show the vibration matching ratio Cxy measured by the eight G sensors with respect to the sound pressure level measured by the microphones 53a and 53b. FIG. 16 shows the matching ratio of vibration to the sound pressure level by the microphone 53b arranged at the right ear position of the driver, and FIG. 17 shows the microphone 53a arranged at the right ear position of the occupant in the rear right seat. The matching ratio of vibration to sound pressure level is shown. Also, the dotted lines in FIGS. 16 and 17 indicate the case of the G sensor arrangement shown in FIG. 14, and the solid line indicates the case of the G sensor arrangement shown in FIG.

As shown in FIG. 16, the matching rate C _xy in the noise frequency band (100 to 600 Hz) is larger in the arrangement shown in FIG. 15 than in the arrangement shown in FIG. However, as shown in FIG. 17, there was no significant difference in the matching rate C _xy at the rear seat. Although the number of G sensors on the tank panel is smaller in the arrangement in FIG. 15 than in the arrangement in FIG. 14, the matching rate is hardly changed (not decreased). From this, it can be said that the arrangement shown in FIG. 15 is more efficient than the arrangement shown in FIG. By repeating such operations, it is possible to optimize the arrangement of the G sensor.

  As shown in FIG. 13, on the floor panel 6 of the vehicle body, there are portions where the rigidity of the tunnel 23, the tank gap 24, etc. is higher than that of other floor panel 6 portions. The vibration transmitted through the floor panel 6 is not easily transmitted to the adjacent areas A to D across the tunnel 23 and the tank gap 24. Therefore, it is possible to define a region where vibration is easily transmitted.

  The purpose of defining a region where vibration is easily transmitted is to determine the arrangement of one or more G sensors (second sensors 2). When one or more G sensors are arranged in each of the areas A to D, most of the vibration from the wheel can be captured by the G sensor.

  The region where vibration is easily transmitted can be defined by the matching ratio between two adjacent G sensors. When the matching ratio takes a minimum value in the horizontal direction or the vertical direction within the surface of the floor panel 6, it means that a highly rigid portion of the floor panel 6 exists at the minimum value. This is because vibration is difficult to be transmitted by a highly rigid portion such as the tunnel 23 or the tank gap 24 in a portion where the matching ratio takes a minimum value.

  As shown in FIG. 18, G sensors are arranged at a plurality of measurement points 60 </ b> A to 60 </ b> H on the floor panel 6, and the vibration of the floor panel 6 is measured by each G sensor. And the correlation of the measured value between adjacent G sensors was calculated | required by experiment on the compact car. FIG. 19 plots the interrelationship of measured values between the G sensors 60F and 60G, between the G sensors 60G and 60C, and between the G sensors 60C and 60H in a direction perpendicular to the traveling direction of the vehicle. FIG. 20 plots the interrelationship of measured values between the G sensors 60A and 60B, between the G sensors 60B and 60C, between the G sensors 60C and 60D, and between the G sensors 60D and 60E in a direction parallel to the traveling direction of the vehicle. did. A tunnel 23 is disposed between the G sensors 60G and 60C, and a tank gap 24 is disposed between the G sensors 60C and 60D. Therefore, the mutual relationship between the measured values between the G sensors 60G and 60C and between the G sensors 60C and 60D is smaller than the surrounding mutual relationship, and takes a minimum value. Therefore, conversely, from the results of these measured values, the tunnel 23 and the tank gap 24 between the G sensors 60G and 60C and between the G sensors 60C and 60D have a stiffness value larger than the average stiffness value of the entire floor panel 6. Etc. can be inferred. By performing the correlation of the measured values between the G sensors for the entire floor panel 6, it is possible to estimate the arrangement of the tunnel 23 and the tank gap 24 that divide the floor panel 6 into a plurality of regions.

  Thus, among the plurality of measurement points defined on the floor panel 6, the vibration matching rate of the floor panel 6 between the adjacent measurement points (correlation between the measured values of the G sensor) is the adjacent measurement point. The floor panel 6 can be divided into a plurality of regions by connecting the midpoints of adjacent measurement points that are smaller than the matching rate in the surrounding area. A plurality of G sensors are arranged in each region. By arranging the G sensor in each of these areas, the control accuracy of the active vibration control device and the active noise control device is improved.

[effect]
As described above, according to the embodiment of the present invention, the sensor (second sensor 2) for measuring the vibration of the vehicle body arranged on the floor panel of the vehicle body and the vibration of the vehicle body measured by the sensor are used. Based on the noise calculation unit 12 that calculates the vehicle interior noise due to the vibration of the vehicle body, the active unit (speaker 3) that generates the control vibration in the vehicle body or the control sound in the vehicle interior, and the vehicle interior calculated by the noise calculation unit 12 A controller 4 that reduces noise caused by vibration of the vehicle body by controlling the active unit 3 according to noise, and the sensor 2 is a floor on which the matching rate between the vibration and noise of the vehicle body measured by the sensor 2 is the strongest. An active vibration noise control device arranged in the panel 6 can be realized. As a result, the sensor can be arranged at an optimal location, so that the number of sensors can be reduced and the cost of the sensor can be reduced while maintaining high vibration / noise reduction performance.

  The floor panel 6 is divided into a plurality of regions by members 18 and 19 having a rigidity value larger than the average value of the rigidity values of the entire floor panel 6, and a plurality of sensors 2 are arranged in each region. Thereby, the matching rate between the measured value of vibration by the sensor and the sound pressure level of noise in the passenger compartment can be increased. Therefore, the vibration / noise reduction performance can be improved.

  As shown in FIG. 18, the floor panel 6 has a vibration matching rate between adjacent measurement points among a plurality of measurement points defined on the floor panel 6. Are divided into a plurality of regions by connecting intermediate points of adjacent measurement points that are smaller than the matching rate. A plurality of sensors are arranged in each region. Thereby, arrangement | positioning of a some sensor can be optimized, said matching rate can be improved, and the reduction performance of a vibration / noise can be improved <the effect of Claim 3>.

  The floor panel 6 may be divided into the same number of regions as the number of passengers. Even in this case, by arranging a plurality of sensors in each region, the arrangement of the plurality of sensors can be optimized, the matching rate is increased, and the vibration / noise reduction performance is improved. <Effects of claim 4>

  As described above, the present invention has been described according to one embodiment. However, it should not be understood that the description and the drawings, which form a part of this disclosure, limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art. That is, it should be understood that the present invention includes various embodiments not described herein. Therefore, the present invention is limited only by the invention specifying matters according to the scope of claims reasonable from this disclosure.

It is a block diagram which shows the structure of the active noise suppression apparatus (ANC) concerning embodiment. It is a block diagram which shows the mode of signal transmission in the active noise suppression apparatus of FIG. It is a block diagram which shows the detailed structure of the noise calculating part of FIG. It is a block diagram which shows the structure of the general active noise control apparatus using an adaptive filter controller. It is a block diagram which shows the mode of signal transmission in the active noise control apparatus of FIG. FIG. 6A is a block diagram showing the relationship between a plurality of input signals and their output signals, and FIG. 6B shows the ratio of each input signal to the output signals (this corresponds to the matching rate). FIG. 6C is a schematic diagram showing a state in which the signal transmission of FIG. 6A is applied to a vehicle. It is a graph which shows the frequency dependence of the matching rate of the vehicle interior noise in a driver | operator's right ear position, and the vibration of a floor panel. FIG. 8A is a cross-sectional view showing a vehicle on which the vibration suppressing device of FIG. 1 is mounted, and FIG. 8B is a plan view showing a floor panel portion of the vehicle of FIG. It is a top view which shows the member arrange | positioned on the floor panel of FIG.8 (b). It is a block diagram which shows the structure of a general active vibration suppression apparatus (AVC). It is a block diagram which shows the structure of the active vibration suppression apparatus (AVC) concerning embodiment. It is a graph which shows the frequency dependence of the damping factor of the vibration measured by 16 sensors arrange | positioned on a floor panel. It is a top view which shows the floor panel divided | segmented by the tunnel and the tank gap. It is a top view which shows the position of the G sensor which measures the vibration of a floor panel, and the position of a microphone, and shows the case where all the G sensors are arrange | positioned behind a tank gap. It is a top view which shows the position of G sensor which measures the vibration of a floor panel, and the position of a microphone, and shows the case where two G sensors are each arrange | positioned in four area | regions AD. It is a graph which shows the matching rate _Cxy of the vibration measured by eight G sensors with respect to the sound pressure level measured by the microphone, and shows the case where the microphone is arranged at the position of the driver's right ear. It is a graph which shows the matching rate _Cxy of the vibration measured by eight G sensors with respect to the sound pressure level measured by the microphone, and the case where the microphone is arranged at the position of the right ear of the occupant of the technical seat at the rear. Show. It is a top view which shows the position of G sensor arrange | positioned on a floor panel. It is the graph which plotted the correlation of the measured value between G sensors of FIG. 18 adjacent to the direction perpendicular | vertical to the advancing direction of a vehicle. It is the graph which plotted the correlation of the measured value between G sensors of FIG. 18 adjacent to the direction parallel to the advancing direction of a vehicle.

Explanation of symbols

1 Acceleration sensor (first sensor)
2 ... Acceleration sensor (second sensor)
3 ... Speaker (active part)
4, 4b ... Controller 5 ... Car body 6 ... Floor panel 7 ... Adaptive filter 8 ... Adaptive low 9 ... System 10a to 10d ... Tire 11 ... Road surface 12 ... Noise calculator 15 ... Cabin panel 16 ... Tank panel 17 ... Spare tire panel 18a -18d ... Vertical members 19a-19d ... Horizontal members 20 ... Actuators 23 ... Tunnel 24 ... Tank gaps 53a, 53b ... Microphones 60A-60H ... Measurement points

Claims (3)

A plurality of sensors disposed on a floor panel of the vehicle body for measuring vibrations of the vehicle body;
Based on the vibration of the vehicle body measured by the sensor, a noise calculation unit that calculates noise in the vehicle interior due to the vibration of the vehicle body;
An active part for generating control vibration in the vehicle body or control sound in the vehicle interior;
A controller for reducing the noise due to vibration of the vehicle body by controlling the active unit according to the noise in the vehicle cabin calculated by the noise calculation unit;
The floor panel is divided into a plurality of regions by members whose rigidity value is larger than an average value of rigidity values of the entire floor panel,
The active vibration and noise control device according to claim 1, wherein the plurality of sensors are respectively disposed in respective regions separated by the member . The floor panel has a matching rate of vibration of the floor panel between adjacent measurement points among a plurality of measurement points defined on the floor panel, which is smaller than the matching rate around the adjacent measurement points. active vibration noise control apparatus according to claim 1, wherein the partitioned into the plurality of areas by connecting the middle point of the measurement points the adjacent. The active vibration noise control device according to claim 1 or 2, wherein the floor panel is divided into the same number of regions as the number of passengers.

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